1. Field of the Invention
Exemplary aspects of the present invention generally relate to an image forming apparatus employing an electrophotographic method such as a printer, copier, or facsimile machine, and more particularly to an image forming apparatus that reliably prevents toner scattering upon detachment of an image forming unit from the image forming apparatus.
2. Description of the Related Art
Related-art image forming apparatuses, such as copiers, printers, facsimile machines, and multifunction devices having two or more of copying, printing, and facsimile capabilities, typically form a toner image on a recording medium (e.g., a sheet of paper, etc.) according to image data using an electrophotographic method. In such a method, for example, a charger charges a surface of an image carrier (e.g., a photoconductor); an irradiating device emits a light beam onto the charged surface of the photoconductor to form an electrostatic latent image on the photoconductor according to the image data; a developing device develops the electrostatic latent image with a developer (e.g., toner) to form a toner image on the photoconductor; a transfer device transfers the toner image formed on the photoconductor onto a sheet of recording media; and a fixing device applies heat and pressure to the sheet bearing the toner image to fix the toner image onto the sheet. The sheet bearing the fixed toner image is then discharged from the image forming apparatus.
In order to meet increasing demand for compact apparatuses with easy maintenance, the photoconductor, the developing device, and so on are often formed together within a cartridge casing as a single integrated image forming unit detachably installable in the image forming apparatus. An example of the image forming unit includes, but is not limited to, a process cartridge including a photoconductor unit (PCU) or a photoconductor development unit (PCDU). Each image forming unit has a toner reception opening connected to a separate toner cartridge so that toner is supplied from the toner cartridge to the developing device included in the image forming unit via the toner reception opening. When the toner cartridge is detached for replacement, however, toner may spill from the toner reception opening and soil the interior and exterior of the image forming apparatus, the user, or both.
Related-art process cartridges employ a configuration in which a slidable shutter member is provided inside a casing of the process cartridge. Installation and detachment of the process cartridge in and from the image forming apparatus slides the shutter open and closed, thereby preventing toner from escaping during installation and detachment. Alternatively, an All-in-One (AIO) system may be employed to form a toner bottle and a process cartridge together as a single integrated unit. Although the configuration employing the AIO system prevents toner from spilling and scattering, when the toner is used up, not only the toner bottle but also the process cartridge must be replaced with a new toner bottle and a process cartridge together at the same time, thereby needlessly increasing costs.
In yet another approach, a closably openable cover is provided to an upper part of the image forming apparatus so that it can be opened even under cramped conditions of installation. However, in a case in which the process cartridge to which the toner cartridge is attached above the process cartridge is used in such an image forming apparatus, upon replacement of the process cartridge or the toner cartridge, it is necessary to close a shutter provided to a discharge opening of the toner cartridge before detachment of the toner cartridge from the image forming apparatus. In addition, the toner cartridge must be detached before detachment of the process cartridge from the image forming apparatus upon replacement of the process cartridge. Consequently, easy replacement of the toner cartridge or the process cartridge is hindered.
In particular, upon replacement of multiple process cartridges used for a full-color image forming apparatus with multiple new process cartridges, respectively, first the toner cartridges are individually detached from the image forming apparatus after the shutters provided to the toner cartridges are closed, and then the process cartridges are individually detached from the image forming apparatus, thereby complicating replacement of the process cartridges. Further, because the toner discharge openings of the toner cartridges are individually closed or opened with the respective shutters upon replacement of the multiple toner cartridges or process cartridges, the installation and detachment of the toner cartridges or the process cartridges in and from the image forming apparatus are further complicated.
A harness or the like is often used to install multiple toner cartridges together at the same time above the multiple process cartridges in the image forming apparatus. However, inadvertently opening the shutters of the toner cartridges after replacement of the process cartridges without noticing the absence of at least one process cartridge in the image forming apparatus causes toner to spill inside the image forming apparatus from the toner cartridge and soils the image forming apparatus.